The present invention relates to crimping tools particularly to hydraulic crimping tools for affixing electrical connectors to wire transmission lines.
Hydraulic tools of this kind have been used for a number of years, as for example, Burndy Corporation HYPRESS Models Y35 and Y35-2. These tools include hydraulically driven dies for crimping electrical connectors onto transmission lines or for splicing transmission lines.
Hydraulic tools of this kind include a die head subassembly containing the crimping dies in which diehead can be rotated 180 degrees relative to operating handles for ease of positioning the crimping dies over a workpiece The hydraulic tool is operated by placing the dies in position over an electrical connector, actuating tool handles to advance a moveable die into position on a connector and to develop sufficient hydraulic force enabling the dies to crimp the connector. Approximately twelve tons of force are developed at the die head during a crimping operation. After crimping is complete, the tool is disengaged by releasing the hydraulic pressure, and retracting the moveable die.
The die head subassembly comprises a unitary C-shaped head defining a die cavity between a fixed upper jaw and a moveable lower jaw The upper jaw is in the form of a crescent and receives a U-shaped die cooperating with the lower die during a crimping operation. The lower jaw is preferably formed integral with a piston ram for sliding movement relative to the C-shaped head for advancing and retracting the lower die with respect to the upper die. The piston ram cooperates with a power cylinder and advances toward the upper die as hydraulic pressure is developed in the cylinder and retracts when the pressure is released.
The piston ram being cylindrical in form is free to rotate with respect to cylinder axis creating an opportunity for misalignment of the upper and lower die members during a crimping operation. As a result it is necessary to restrain the piston ram from rotation in order to have proper alignment of crimping dies.
In addition, crimping tools can become jammed when non-linear (i.e. non axial) forces are encountered when crimping odd-shaped connectors. The jamming occurs through tilting or cocking of the piston ram in the power cylinder when such non-linear forces are encountered Such jamming can be corrected by adding significant mass to the head to physically encapsulate the piston within the head. However, this results in a heavy and cumbersome tool head.